Kernel version not changing even though the new version is installed

Question

Recently performed software update on a RHEL 6.6 (Santiago). Noticed that kernel version is not updated to latest one that was installed.

kernel version before doing software update:

[root@server01 ~]# uname -r
2.6.32-431.11.2.el6.x86_64

Below is the summary of kernel packages from yum list command:

[root@server01 ~]# yum list kernel
Loaded plugins: amazon-id, rhui-lb, security
Installed Packages
kernel.x86_64              2.6.32-431.11.2.el6              installed
kernel.x86_64              2.6.32-504.12.2.el6              @rhui-REGION-rhel-server-releases
kernel.x86_64              2.6.32-504.16.2.el6              @rhui-REGION-rhel-server-releases
Available Packages
kernel.x86_64              2.6.32-504.23.4.el6              rhui-REGION-rhel-server-releases

Expecting the kernel would be updated to highest version among the installed ones. But it changed as below even after couple of reboots.

[root@server01 ~]# uname -r
**2.6.32-504.12.2.el6.x86_64**

Any ideas? thanks!

Solution

While I'm unable to explain why the newest kernel wasn't booting automatically, the kernel booted by GRUB is set in /boot/grub/grub.conf using the default=<menu entry number>, where counting starts at 0. In this specific case, default=1 will boot your desired kernel.

Comments

[Liczyrzepa]

Run the following: "ls /boot ; uname -a". If the new kernel version is in /boot, check /boot/grub/grub.conf.

[taki]

@Liczyrzepa Yes, the new kernel is in /boot folder. In file /boot/grub/grub.conf the kernel entries are in the following order: title Red Hat Enterprise Linux Server (2.6.32-504.12.2.el6.x86_64) title Red Hat Enterprise Linux Server (2.6.32-504.16.2.el6.x86_64) title Red Hat Enterprise Linux (2.6.32-431.11.2.el6.x86_64)

[Liczyrzepa]

ok - so what is the default set to? My guess is that is says default=0, but you want default=1 to boot -504.16.2. Generally, updating will place the newest kernel at the head of the list, so I'm not sure what happened there. Also, ATM, 2.6.32-504.23.4 is the latest. You may want to run "yum upgrade" or "yum update" and check again.

[taki]

@Liczyrzepa Thanks. changed from "default=0" to "default=1" and rebooted. Now the kernel in use has changed to the latest installed one.